1. Field of the Invention
The present invention relates to methods and apparatus for implanting devices in the wall of a hollow organ, including devices to reduce the volume of the stomach.
2. Description of the Related Art
Obesity is a public health problem of growing national and international importance. There are an estimated 60 million obese adults and 2 million obese adolescents in the United States as of 2004. By some estimates, there are 1 billion obese individuals worldwide.
Over the past four decades, there have been numerous surgical procedures and devices developed to treat the morbidly obese. In general, there are two physiologic aspects of all past and current procedures: malabsorption and mechanical restriction/volume reduction.
Many of the procedures performed in the past have proven to be impractical, dangerous, or detrimental to the health of the patients and are now of historical importance only. An example of a failed procedure is the jejunal-ileo bypass in which a malabsorptive state is created through the bypass of a large portion of the intestine through the creation of a surgical anastamosis between the jejunum and the ileum. While patients initially lost a great deal of weight, liver failure or liver damage occurred in over one-third of the patients which necessitated reversal of the surgical procedure.
The Roux-en-Y (The Roux) bypass operation has evolved to become the most commonly performed surgical procedure to treat the morbidly obese. It combines a small degree of malabsorption with a 90% reduction in the volume of the stomach. In the United States, 150,000 procedures are predicted for the year 2004. This number is expected to rise to 500,000 procedures by 2006. The procedure has been performed since the late 1970's and the long-term data has been very good. The advent of laparoscopic surgery and hence the laparoscopic Roux-en-Y bypass in combination with excellent follow-up results from the open procedure are reasons for the proliferation of the Roux procedure.
Despite the efficacy of the Roux procedure and the recent laparoscopic improvements, it remains a highly invasive procedure with substantial morbidity including a 1-2% surgical mortality, a 20-30% incidence of pulmonary morbidity such as pneumonia, pulmonary embolism, etc., and a 1-4% chance of leak at the anastamotic site which can result in a spectrum of consequences including an extended hospital stay to death.
The Roux procedure requires general anesthesia and muscle paralysis which, in the morbidly obese population, is not of small consequence. There is also a substantial rate of anastamotic stricture which results in severe lifestyle changes for patients. For example, many patients are forced to vomit after meals.
The largest problem from the perspective of the patient is that the Roux-en-Y is not reversible, which dramatically limits the number of patients willing to undergo the procedure. In particular, it severely limits the number of procedures which can or should be performed on adolescents.
The Magenstrasse and Mill (M&M) procedure is an evolving technique wherein the greater curvature of the stomach is essentially taken out of the path of food, leaving a tube of stomach, the Magenstrasse, or street of the stomach, comprised of the lesser curvature. The antrum is preserved in this procedure. The theory behind leaving the antral “mill” is that it will continue to serve its normal function of mixing, grinding, retropulsion, and well-regulated expulsion of chyme into the duodenum. An authoritative study on the operation is incorporated herein by reference (Johnston et. al. The Magenstrasse and Mill Operation for Morbid Obesity; Obesity Surgery 13, 10-16).
Percutaneous Endoscopic Gastrostomy (PEG) refers to a procedure in which a gastrocutaneous tract is created using percutaneous means. A recent update of the procedure can be found on the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) website, and is incorporated herein by reference. Briefly, the procedure involves insufflation of the stomach with and under visualization with an endoscope. A small incision is made in the skin and a needle is advanced into the stomach (the stomach sits just under the abdominal wall when insufflated) under endoscopic visualization. A feeding tube is then placed over the needle to create a gastrocutaneous tract with the feeding tube inside the tract. The feeding tube is secured with an external bolster. Over the ensuing weeks, a permanent tract evolves between the stomach mucosa and epithelium of the skin, after which, the bolster can be removed without consequence. When the feeding tube is to be removed, the gastrocutaneous tract will close on its own as food will preferentially be delivered antegrade (the path of least resistance) to the duodenum, thereby allowing the tract to heal.
Recently, minimally invasive procedures and devices which create a feeling of early satiety have been introduced into the marketplace. The LAP-BAND™ is a band which encircles the stomach at the region of the fundus-cardia junction. It requires general anesthesia, a pneumoperitoneum, muscle paralysis, and extensive dissection of the stomach at the level the gastroesophageal junction. Although less invasive than the Roux procedure and potentially reversible, the LAP-BAND™ is nonetheless quite invasive. It also does not reduce the volume of the stomach and patients report a feeling of hunger much of the time.
More recently, there has been an effort to develop even less invasive devices and procedures which do not involve incisions at all. For the most part, these procedures are performed from within the stomach with an endoscope and by a phyisician with a high degree of endoscopic skill. For example, U.S. Pat. No. 6,558,400 describes methods and devices to create partitions in the stomach. Fasteners or staplers applied through an endoscope from within the stomach are used to accomplish the partitions. Similarly, U.S. patent application Publication No. 2004/0122456 describes another set of methods and devices to reduce the volume of the stomach. Expandable anchors are deployed both on the anterior and posterior wall of the stomach by way of an endoscope. Flexible sutures are brought out of the patient's mouth and the sutures are crimped together within the stomach in order to bring the walls of the stomach closer together. Patent application WO2004/004542 describes a device which is advanced through an endoscope and grasps or applies suction to a fold of mucosa to apply fasteners through the mucosal and serosal layers of the stomach.
Endoscopic procedures to manipulate the stomach are time consuming because of the technical difficulty of the endoscopy; they also require a large endoscope through which many instruments need to be placed for these complex procedures. Due to the large girth of the endoscope, patients typically will require general anesthesia, limiting the “non-invasive” aspects of the procedure. Furthermore, the procedures require advanced endoscopic skill which would need to be acquired by most practitioners. Such skill adaptation can take a significant amount of time, which will limit adoption of the procedure by the physician community. A further issue is that there is a limitation on the size of the anchors which can be placed because the endoscope has a maximum size.